package com.example.demo.util;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class MD5Util {
	 // 全局数组
    private final static String[] strDigits = { "0", "1", "2", "3", "4", "5",
            "6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };

    public MD5Util() {
    }

    // 返回形式为数字跟字符串
    private static String byteToArrayString(byte bByte) {
        int iRet = bByte;
        // System.out.println("iRet="+iRet);
        if (iRet < 0) {
            iRet += 256;
        }
        int iD1 = iRet / 16;
        int iD2 = iRet % 16;
        return strDigits[iD1] + strDigits[iD2];
    }

    // 返回形式只为数字
    public static String byteToNum(byte bByte) {
        int iRet = bByte;
        System.out.println("iRet1=" + iRet);
        if (iRet < 0) {
            iRet += 256;
        }
        return String.valueOf(iRet);
    }

    // 转换字节数组为16进制字串
    public static String byteToString(byte[] bByte) {
        StringBuffer sBuffer = new StringBuffer();
        for (int i = 0; i < bByte.length; i++) {
            sBuffer.append(byteToArrayString(bByte[i]));
        }
        return sBuffer.toString();
    }

    public static String GetMD5Code(String strObj) {
        try {
            MessageDigest md = MessageDigest.getInstance("MD5");
    		byte[] inputByteArray = strObj.getBytes();
    	    md.update(inputByteArray);
    	    byte[] bytes = md.digest();
            StringBuffer builder = new StringBuffer();
 			String temp = null;
 			for (int i = 0; i < bytes.length; i++) {
 				temp = Integer.toHexString(bytes[i] & 0xFF);
 				if (temp.length() == 1) builder.append("0");
 				builder.append(temp);
 			}
            return builder.toString();
        } catch (NoSuchAlgorithmException ex) {
            ex.printStackTrace();
        }
        return null;
    }

    public static void main(String[] args) {
    	String md5 = MD5Util.GetMD5Code("123456");
        System.out.println(md5);
        System.out.println(md5.equals("e10adc3949ba59abbe56e057f20f883e"));
    }
}